1. Field of the Invention
The present invention relates generally to blower units and more specifically to blower units of the type used with spa pools and baths which are commonly called spa blowers or spa bath blowers, and for illustrative purposes reference will be made to such application. Typically such units include a fan unit which is close coupled to an electric motor, with the fan impeller being directly mounted on the motor drive shaft and enclosed in a fan casing. It will be appreciated that the invention may have application in other fields where a vacuum supply is required and thus reference to the invention as a blower unit is not to be taken as restricting the invention to only that use.
2. Discussion of the Prior Art
Australian Patent No. 599,909 granted to the present applicant, describes a blower unit in which cooling air for the drive motor follows a different path from that of the feed air for the blower even though all air enters the unit housing through the same inlet ports. That arrangement overcomes, or at least ameliorates some of the problems associated with other blower units in which the blower draws feed air over or through the drive motor in order to cool the drive motor. As described in patent No. 599,909, reduction of the blower output through blockage or heavy load results in insufficient feed air being drawn over or through the drive motor and causes consequential overheating of the motor. Although the blower unit described in patent No. 599,909 has significant benefits over other blower units, it is not as compact as desired for some applications.
Accordingly, there is a clearly felt need in the art for a blower unit, which is sufficiently compact to satisfy at least some market requirements for more efficient compact blowers, has separate air flow paths for the drive motor, and has relatively low noise emission.